Each trial started with the presentation of one stimulus (one of the rings or the square). After 500 ms, the rating
scale appeared at the bottom of the screen. This scale ranged from 0 (left) over 5 (middle) to 10 (right), with
tickmarks indicating (but not showing) 1, 2, 3, etc. In addition, position 0 was accompanied by the label “Certainly
no lightning”, 5 was accompanied by “Uncertain”, and 10 was accompanied by “Certainly lightning”. Participants
indicated their expectancy by moving the pointer with the left and right arrow keys (the initial position of the
pointer was always 5). Their final judgement was registered when they clicked the key. At that moment,
the stimulus and the rating scale disappeared from the screen, and immediately the lightning stimulus was either
presented (for 1500 ms) or not. After that, the intertrial interval started in anticipation of the next stimulus presentation